Impact Of The Sunspot And SOI On The Upper Yellow River Runoff

Water resources system and hydro-environment are vast, variant and nonlinear system. The variance of runoff, which is the main factor in the system and dominants the variance of the whole system, has important effects on social economy, environment and water resources of the district. Because of the synthesis influence of weather, geography and human lactivoty, runoff of the Yellow River basin is complicated, multi-time-scale dependent, random, discontinuous, and non-linear etc. Traditional methods of runoff analysis and prediction are difficult to get satisfactory results and face researchs, For the integrated management and sustainable development of the Yellow River basin, many effects have been made to analyze its runoff characteristic and carry out its runoff forecast, including many domestic and international research programs. Yellow River research is becoming one of the typical study basins in water science.This thesis, according to the hydrological records (such as runoff, sunspot, SOI, precipitation and atmospheric temperature), applies modern new theories (such as wavelet transformation, artificial nerve network theory) and traditional methods, to systematically study the periods of runoff, sunspot, SOI, precipitation and atmospheric temperature. Based on such analyses, this study discovers the effect of the hydrographic features on the long variety regime of the runoff, and understands the long term regulation of the upper Yellow River runoff. Meanwhile, using the GRNN network and hydrological data, simulation and verification of the monthly runoff from 1961 to 1998, and analysis of the effect of sunspot and SOI areconducted. Principal findings are concluded as follows.Firstly, it is revealed that cycles of high and low flows in the upper Yellow River alternately occur, but the time of the high flow is less than that of low one on the whole, and the period of an integrated high and low flow cycle is about 18 years. The annual runoff tends to weak increase from 1920 to 1998, and it is expected that the runoff will present a state of high flows. The annual average runoff is 617m~3/s in upper Yellow River, and runoff mainly concentrated in Jun to Oct. In changing trend and influence months, monthly average runoff, precipitation and atmospheric temperature have high correlation. Under the condition of global warming, the atmospheric temperature tends to fluctuating increase, but the precipitation and runoff tend to fluctuating drop after 1990s.Secondly, sunspot, SOI, precipitation, atmospheric temperature and annual runoff have similar periodical fluctuation with different resolutions.Thirdly, the results display that the sunspot and annual runoff respectively have about 11 and 2-3 years' period, which dominant the long time variety characteristic of the annual sunspot and runoff. The research shows that there are high correlation and regularity between sunspot and runoff during the magnetic period.Fourthly, the major periods of the SOI are about 2 years, and there are other different periodicities in multi-time scales of the series, Especially SOI has strong negative relations with the upper Yellow River runoff during the periods of 40~50, 20, and 10 years. The occurring rate of the ENSO warm phrase event increase, on the contrary, the cold phase event reduce .the Annual runoff has decrease trend in the upper Yellow River because of the warm phase event.Finally, in this study, modern new theories and methods are pplied to the upper Yellow River to analyze the long-term variant characteristic of its annual and monthly runoff. Its research and the analysis methods provide intending variety foreground of runoff for decision-making, research and public.